Mobile LCD presentations, such as may be found in buses or trains, as well as in stationary LCDs in depots, possess one or more electrically controllable LCD-cells. A single LCD-cell has, in such displays, two, parallel, transparent plates, one behind the other, between which a liquid crystal is captured. Electrodes are arranged on the plates, for example, as a transparent electrode coating, which can be comprised of a plurality of controllable elements. If a voltage is applied between the electrodes, that is, between the individual elements, then certain areas of the LCD-cell with either appear bright or as a “Normally Black Mode LCD”, i.e., dark. Conversely, without applied potential, the areas will appear reversed as to bright and dark.
In the case of non-horizontally disposed LCD-cells, the liquid crystals collect, as a result of gravity, in a lower zone. In this case, first, the distribution of wall to wall distance inside the cells in a direction parallel to the two plates changes, and second, the transparent plates in the lower zone are pressed away from one another, but simultaneously draw together in the upper zone. The same holds true, of course, when inertial force is substituted for gravity force when horizontally or vertically mounted displays are accelerated. This leads to undesirable irregularities of the colors within areas of the display.
In order to prevent this, a known solution of the problem is that between the plates, transparent or dark spacers are inserted, which are mostly made of glass or plastic and are fastened between the two plates by means of an elastic adhesive material. This prevents an approach of one plate to the other in the upper zone as well as assuring an equalized distancing of one plate from the other in the lower zone. These spacer materials, however, when compared with liquid crystal, exhibit a heat expansion coefficient which is clearly, by an amount of one or two magnitudes, smaller than that of the liquid crystal. This may be expressed as   α  =            (              V        -                  V          o                    )              [              V        ⁡                  (                      t            -                          t              o                                )                    ]      wherein V and Vo represent the volumes of a body at the temperatures t and to, respectively.
If the LCD-cell warms, for instance from 20° C. to 85° C., then the liquid crystal expands itself essentially more than do the spacers and consequently presses the transparent plates away from one another. When this occurs, the spacers, which are adhesively affixed to the plates by at least one end are freed, that is, the spacers clamped between the plates are clearly relieved of pressure stress. Under these conditions, gravity causes the liquid crystals to settle, resulting in an expansion of the lower zone and relative thereto, also a narrowing of the upper zone, which again leads to an undesirable loss of uniformity of color at higher temperatures.
Conversely, if the LCD-cell cools within a range of from 20° C. to −30° C., then the liquid crystals contract to a greater extend than the spacers. On this account, the plates are unable to sufficiently follow the shrinking of the liquid crystals, whereby, in scattered locations, vacuum voids form in the liquid crystals, which produce a disturbing appearance. If, on the other hand, the spacers are so yielding that the possibility arises that their elastic contraction is commensurate with the diminishing volume of the liquid crystals, this brings about an undesirable macroscopic alteration of the thickness of the layer, that is, the distance apart of the two facing surfaces of the transparent plate, otherwise known as the “cell gap” of the LCD-cell.
If the spacers are not fastened by adhesion, but by flexible clamping between the two plates, then these spacers, upon vibration of the LCD-cell, approximately in the manner of a conventional vibration test, or in mobile operation, fall into micro-motions, which in turn lead to undesirable scratches on the surface of the transparent plates.
This problem is reinforced by operation at higher temperatures when the spacers, because the expansion of the LCD-cell are less strongly restrained.